Question

I have a table with columns, a, b, c, d, e.

Each column is given a random numerical value.

I can then order by that numerical value.

query_results = UserProfile.objects.all().order_by('a')

What i want is the ability to order by the sum of 2 or 3 or even 5 columns. But i cant figure out how to do it lightly.

My answer so far has been some what convoluted. I add an extra column x.

cursor.execute("UPDATE mysite_userprofile SET x = a+b;")

I then order by x. I have to update the column x each time i want different columns added together.

This is not the way to do it i know. i know order_by(‘a+b’) doesn’t work but is their another solution just as simple. I looked on django’s site but couldn’t find anything

Answer 1

The best way is to use extra

UserProfile.objects.extra(
    select={'sum_of_fields': 'a + b + c + d + e'},
    order_by=('sum_of_fields',)
)